ACK/cmnt: [PATCH][OEM][Artful] drm/i915: Apply Display WA #1183 on skl, kbl, and cfl
Stefan Bader
stefan.bader at canonical.com
Wed Mar 28 12:39:10 UTC 2018
On 28.03.2018 05:20, AceLan Kao wrote:
> From: Lucas De Marchi <lucas.demarchi at intel.com>
>
> BugLink: https://launchpad.net/bugs/1759188
>
> Display WA #1183 was recently added to workaround
> "Failures when enabling DPLL0 with eDP link rate 2.16
> or 4.32 GHz and CD clock frequency 308.57 or 617.14 MHz
> (CDCLK_CTL CD Frequency Select 10b or 11b) used in this
> enabling or in previous enabling."
>
> This workaround was designed to minimize the impact only
> to save the bad case with that link rates. But HW engineers
> indicated that it should be safe to apply broadly, although
> they were expecting the DPLL0 link rate to be unchanged on
> runtime.
>
> We need to cover 2 cases: when we are in fact enabling DPLL0
> and when we are just changing the frequency with small
> differences.
>
> This is based on previous patch by Rodrigo Vivi with suggestions
> from Ville Syrjälä.
>
> Cc: Arthur J Runyan <arthur.j.runyan at intel.com>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: stable at vger.kernel.org
> Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Link: https://patchwork.freedesktop.org/patch/msgid/20171204232210.4958-1-lucas.demarchi@intel.com
> (cherry picked from commit 53421c2fe99ce16838639ad89d772d914a119a49)
> [ Lucas: Backport to 4.15 adding back variable that has been removed on
> commits not meant to be backported ]
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
> Link: https://patchwork.freedesktop.org/patch/msgid/20180102201837.6812-1-lucas.demarchi@intel.com
>
> (cherry picked from commit 30414f3010aff95ffdb6bed7b9dce62cde94fdc7)
> Signed-off-by: AceLan Kao <acelan.kao at canonical.com>
Acked-by: Stefan Bader <stefan.bader at canonical.com>
> ---
This seems to have been part of 4.15-rc7 so should be included in Bionic already.
> drivers/gpu/drm/i915/i915_reg.h | 2 ++
> drivers/gpu/drm/i915/intel_cdclk.c | 35 ++++++++++++++++++++++++---------
> drivers/gpu/drm/i915/intel_runtime_pm.c | 10 ++++++++++
> 3 files changed, 38 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 91b1e92..c53d369 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6748,6 +6748,7 @@ enum {
> #define RESET_PCH_HANDSHAKE_ENABLE (1<<4)
>
> #define GEN8_CHICKEN_DCPR_1 _MMIO(0x46430)
> +#define SKL_SELECT_ALTERNATE_DC_EXIT (1<<30)
> #define MASK_WAKEMEM (1<<13)
>
> #define SKL_DFSM _MMIO(0x51000)
> @@ -8256,6 +8257,7 @@ enum {
> #define BXT_CDCLK_CD2X_DIV_SEL_2 (2<<22)
> #define BXT_CDCLK_CD2X_DIV_SEL_4 (3<<22)
> #define BXT_CDCLK_CD2X_PIPE(pipe) ((pipe)<<20)
> +#define CDCLK_DIVMUX_CD_OVERRIDE (1<<19)
> #define BXT_CDCLK_CD2X_PIPE_NONE BXT_CDCLK_CD2X_PIPE(3)
> #define BXT_CDCLK_SSA_PRECHARGE_ENABLE (1<<16)
> #define CDCLK_FREQ_DECIMAL_MASK (0x7ff)
> diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c
> index b156032..7ca6f4f 100644
> --- a/drivers/gpu/drm/i915/intel_cdclk.c
> +++ b/drivers/gpu/drm/i915/intel_cdclk.c
> @@ -856,16 +856,10 @@ static void skl_set_preferred_cdclk_vco(struct drm_i915_private *dev_priv,
>
> static void skl_dpll0_enable(struct drm_i915_private *dev_priv, int vco)
> {
> - int min_cdclk = skl_calc_cdclk(0, vco);
> u32 val;
>
> WARN_ON(vco != 8100000 && vco != 8640000);
>
> - /* select the minimum CDCLK before enabling DPLL 0 */
> - val = CDCLK_FREQ_337_308 | skl_cdclk_decimal(min_cdclk);
> - I915_WRITE(CDCLK_CTL, val);
> - POSTING_READ(CDCLK_CTL);
> -
> /*
> * We always enable DPLL0 with the lowest link rate possible, but still
> * taking into account the VCO required to operate the eDP panel at the
> @@ -919,7 +913,7 @@ static void skl_set_cdclk(struct drm_i915_private *dev_priv,
> {
> int cdclk = cdclk_state->cdclk;
> int vco = cdclk_state->vco;
> - u32 freq_select, pcu_ack;
> + u32 freq_select, pcu_ack, cdclk_ctl;
> int ret;
>
> WARN_ON((cdclk == 24000) != (vco == 0));
> @@ -936,7 +930,7 @@ static void skl_set_cdclk(struct drm_i915_private *dev_priv,
> return;
> }
>
> - /* set CDCLK_CTL */
> + /* Choose frequency for this cdclk */
> switch (cdclk) {
> case 450000:
> case 432000:
> @@ -964,10 +958,33 @@ static void skl_set_cdclk(struct drm_i915_private *dev_priv,
> dev_priv->cdclk.hw.vco != vco)
> skl_dpll0_disable(dev_priv);
>
> + cdclk_ctl = I915_READ(CDCLK_CTL);
> +
> + if (dev_priv->cdclk.hw.vco != vco) {
> + /* Wa Display #1183: skl,kbl,cfl */
> + cdclk_ctl &= ~(CDCLK_FREQ_SEL_MASK | CDCLK_FREQ_DECIMAL_MASK);
> + cdclk_ctl |= freq_select | skl_cdclk_decimal(cdclk);
> + I915_WRITE(CDCLK_CTL, cdclk_ctl);
> + }
> +
> + /* Wa Display #1183: skl,kbl,cfl */
> + cdclk_ctl |= CDCLK_DIVMUX_CD_OVERRIDE;
> + I915_WRITE(CDCLK_CTL, cdclk_ctl);
> + POSTING_READ(CDCLK_CTL);
> +
> if (dev_priv->cdclk.hw.vco != vco)
> skl_dpll0_enable(dev_priv, vco);
>
> - I915_WRITE(CDCLK_CTL, freq_select | skl_cdclk_decimal(cdclk));
> + /* Wa Display #1183: skl,kbl,cfl */
> + cdclk_ctl &= ~(CDCLK_FREQ_SEL_MASK | CDCLK_FREQ_DECIMAL_MASK);
> + I915_WRITE(CDCLK_CTL, cdclk_ctl);
> +
> + cdclk_ctl |= freq_select | skl_cdclk_decimal(cdclk);
> + I915_WRITE(CDCLK_CTL, cdclk_ctl);
> +
> + /* Wa Display #1183: skl,kbl,cfl */
> + cdclk_ctl &= ~CDCLK_DIVMUX_CD_OVERRIDE;
> + I915_WRITE(CDCLK_CTL, cdclk_ctl);
> POSTING_READ(CDCLK_CTL);
>
> /* inform PCU of the change */
> diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c
> index 5eb9c5e..efe8227 100644
> --- a/drivers/gpu/drm/i915/intel_runtime_pm.c
> +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c
> @@ -769,6 +769,11 @@ void gen9_enable_dc5(struct drm_i915_private *dev_priv)
>
> DRM_DEBUG_KMS("Enabling DC5\n");
>
> + /* Wa Display #1183: skl,kbl,cfl */
> + if (IS_GEN9_BC(dev_priv))
> + I915_WRITE(GEN8_CHICKEN_DCPR_1, I915_READ(GEN8_CHICKEN_DCPR_1) |
> + SKL_SELECT_ALTERNATE_DC_EXIT);
> +
> gen9_set_dc_state(dev_priv, DC_STATE_EN_UPTO_DC5);
> }
>
> @@ -796,6 +801,11 @@ void skl_disable_dc6(struct drm_i915_private *dev_priv)
> {
> DRM_DEBUG_KMS("Disabling DC6\n");
>
> + /* Wa Display #1183: skl,kbl,cfl */
> + if (IS_GEN9_BC(dev_priv))
> + I915_WRITE(GEN8_CHICKEN_DCPR_1, I915_READ(GEN8_CHICKEN_DCPR_1) |
> + SKL_SELECT_ALTERNATE_DC_EXIT);
> +
> gen9_set_dc_state(dev_priv, DC_STATE_DISABLE);
> }
>
>
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